Drug Linked to Fewer Deaths Among Kidney Patients
University of North Carolina at Chapel Hill researchers report a 50 percent
reduction in the number of deaths among kidney hemodialysis patients who are
given a new drug that helps prevent excess phosphorus from accumulating in the
"The drug, lanthanum carbonate, is effective. It's well-tolerated, and patients
find it reasonably easy to take," said Dr. William Finn, nephrologist and
professor of medicine at UNC.
Study findings will be presented Saturday (Nov. 2) at the American Society of
Nephrology annual meeting in Philadelphia.
than 350,000 people in the United States receive treatment for kidney failure,
or end-stage renal disease, according to the National Institutes of Health. Of
these, about 60 percent undergo hemodialysis, a process that removes wastes and
excess fluid from the bloodstream by passing it through a membrane in an
artificial kidney machine.
Although regular hemodialysis treatment helps maintain life, studies show it
provides about a tenth of the cleaning function of normal kidneys. Moreover,
those on the treatment run an increased risk of cardiovascular disease and other
"One of the things hemodialysis does not do well is remove phosphorus from the
blood," Finn said. "About 50 to 60 percent of patients on chronic hemodialysis
do not have adequate phosphorus control; they have high phosphorus levels."
Finn added that elevated blood levels of phosphorus help trigger
hyperparathyroidism, a condition that may lead to serious bone and
cardiovascular problems. Some research indicates an increased risk for cardiac
death possibly due to a buildup of calcium in coronary blood vessels.
Moreover, beginning in 1998, reports in medical literature have identified
elevated phosphorus blood levels as independent risk factors for mortality among
kidney patients on hemodialysis. The National Kidney Foundation has subsequently
lowered its recommended phosphorus blood levels.
Today, many kidney failure patients undergoing hemodialysis take medications
that bind dietary phosphorus, thereby allowing its excretion in the stool rather
than its absorption by the body.
Originally, aluminum hydroxide or aluminum containing compounds were used
"because aluminum binds phosphorus very well," Finn said. "Unfortunately, some
of the aluminum was absorbed and found its way into bone and brain tissue,
causing serious bone disease and a condition known as dialysis dementia."
Other phosphorus or phosphate binding agents were then used, including calcium
carbonate (a main ingredient in popular stomach relievers) and calcium acetate.
However, some patients using these calcium-based binders develop hypercalcemia,
high calcium levels, prompting a search for other types of phosphate binders.
Recently, a non-calcium phosphate binder, Renagel, has come into use. Its maker,
Genzyme Corp., sponsored a major clinical study in which hemodialysis patients
taking their drug showed less coronary artery calcification than did patients
taking calcium-based phosphate binders. However, differences in cardiac
mortality among patients in the different drug group binders were not
demonstrated in that study, Finn said. A separate study addressing this issue is
The UNC investigation involves the newly developed, non-calcium phosphate
binder, lanthanum carbonate (Fosrenol), developed by Shire Pharmaceuticals
Group, PLC, in the United Kingdom and not yet federally approved for use in the
Lanthanum is a rare earth element, a heavy metal that binds phosphorus. Results
of a study of bone biopsies in the United States and Europe earlier this year
found no abnormalities, Finn said.
"In addition, there's no evidence that lanthanum crosses the blood-brain
barrier. Tests of cognitive function are being used to determine any central
nervous system changes with Fosrenol use."
In the randomized two-year study, 647 kidney hemodialysis patients received
lanthanum carbonate therapy and 642 patients received conventional phosphate
binders. Patients ranged in age from 19 to 91 years. The first interim analysis
indicated a reduction in mortality in the Fosrenol group, compared to those
taking conventional drug therapy. A second interim analysis indicated a widening
disparity with a reduction in mortality of about 50 percent (3.3 percent versus
5.8 percent). Moreover, fewer people died of what appear to be cardiac factors.
"I think this drug, Fosrenol, or drugs like it will become the preferred
phosphate binders," Finn said.
University of North Carolina School of Medicine
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